Heat exchanger for aircraft engine

ABSTRACT

A heat exchanger for an aircraft engine includes: a body including a plate-like first member and a plate-like second member that are stacked in a thickness direction of the first and second members and joined together, and a channel which is defined in the body and in which the cooling target fluid flows; and a corrugated fin plate disposed in the channel in the body. The body is bent along a curved surface to which the heat exchanger is attached. A plurality of heat dissipation fins stand on an outer surface of at least one of the first member or the second member.

TECHNICAL FIELD

The technique disclosed herein relates to heat exchangers for use inaircraft engines, and particularly to a heat exchanger for cooling, forexample, lubricating oil of an engine or lubricating oil of a generatordriven by the engine.

BACKGROUND ART

Patent Document 1 describes a heat exchanger attached to a gas turbineengine for an aircraft and cooling fluid to be cooled, which will behereinafter referred to as cooling target fluid, such as lubricating oilof the engine. The heat exchanger has an arcuate shape attached to, andextending along, for example, the inner peripheral surface of a fancasing of the gas turbine engine, and is exposed to an airflow passingthrough the gas turbine engine. In the arcuate heat exchanger, aplurality of channels in which cooling target fluid flows are arrangedside by side along the airflow. A large number of heat dissipation finsstand on the outer surface of the heat exchanger. An inflow header forallowing cooling target fluid to flow into the inside channels and anoutflow header for allowing cooling target fluid to flow out of theinside channels are attached to both ends of the arcuate heat exchanger.

Such an arcuate heat exchanger advantageously has a miniaturized sizeand a reduced resistance of an airflow flowing in a gas turbine engine.

CITATION LIST Patent Document

-   [Patent Document 1] Japanese Unexamined Patent Publication No.    2008-144752

SUMMARY OF THE INVENTION Technical Problem

Regarding fabrication of an arcuate heat exchanger, Patent Document 1describes that a body including a plurality of channels is formed byextruding a metallic material such as aluminium and heat dissipationfins are attached to the body by welding or brazing. However, it isgenerally difficult to attach a large number of heat dissipation fins tothe outer surface of the body without fail by welding or brazing. Inaddition, a failure in attaching the heat dissipation fins to the bodywould significantly reduce heat transmission performance, resulting indegradation of performance of the heat exchanger. It is also difficultto inspect whether the heat dissipation fins are attached to the bodywithout fail or not after the heat dissipation fins have been attachedto the body by welding or brazing.

Patent Document 1 also describes that the heat dissipation fins areformed by conducting an “integral fin forming process” on the bodyformed by extrusion, not by joining separate heat dissipation fins tothe body after the formation of the body. Although not specificallydescribed in Patent Document 1, this “integral fin forming process” issupposed to be employed to form a large number of heat dissipation finson the outer surface of the body by obliquely scraping a thin surfaceportion of the body formed by extrusion such that the heat dissipationfins stand on the outer surface. This process ensures that the heatdissipation fins and the body can be continuous such that heat istransmitted therebetween.

The process, however, has a limitation on the relationship between theheight of the heat dissipation fins and the pitch (i.e., the distancebetween adjacent fins) of the heat dissipation fins. Specifically, anincrease in height of the heat dissipation fins requires an increase inlength of the oblique scraping, and the pitch of the heat dissipationfins increases. On the other hand, a decrease in pitch of the heatdissipation fins requires a reduction in length of the oblique scraping,and the height of the heat dissipation fins decreases. In terms ofenhancement of heat exchanger performance, it is preferable that theheight of the heat dissipation fins increases and the pitch of the heatdissipation fins decreases. However, it is difficult for theabove-described process to achieve both the increase in height and thedecrease in pitch.

In addition, as described in Patent Document 1, in the process offorming the body by extrusion, a header member as a separate member fromthe body needs to be joined to the body after the process. This alsoincreases the weight of the heat exchanger.

Further, the process of forming the body by extrusion can determine thedirection of channels only in one direction that coincides with theextrusion direction. Thus, if the heat exchanger is configured such thatthe channel of cooling target fluid makes a U-turn, at least a headerfor the U-turn needs to be joined to the body. This configurationincreases the weight of the heat exchanger, in a manner similar to theconfiguration described above.

It is therefore an object of the present to provide a heat exchangerthat is to be used for an aircraft engine and can be reduced in size andweight with desired performance.

Solution to the Problem

A technique disclosed herein is directed to a heat exchanger for anaircraft engine. This heat exchanger is disposed along a curved surfacein the aircraft engine and configured to cool cooling target fluid whenbeing exposed to an airflow flowing in the engine, and the heatexchanger includes: a body including a plate-like first member and aplate-like second member that are stacked in a thickness direction ofthe first and second members and joined together, and a channel which isdefined in the body and in which the cooling target fluid flows; and acorrugated fin plate disposed in the channel in the body, wherein thebody is bent along the curved surface, and a plurality of heatdissipation fins stand on an outer surface of at least one of the firstmember or the second member.

The heat exchanger with this configuration is disposed along the curvedsurface of the aircraft engine, and cools cooling target fluid whenbeing exposed to an airflow flowing in the engine. This heat exchangeris a so-called surface cooler.

The body of the heat exchanger is formed by stacking the plate-likefirst and second members in the thickness direction and joining thesemembers together, and is not formed by extrusion as described in PatentDocument 1. Thus, as described above, heat dissipation fins are formednot by such a process of scraping a thin surface portion of the extrudedproduct and causing the scraped portion to stand, but by at leastpartially removing, e.g., cutting, the outer surface of the plate-likefirst member and/or the outer surface of the plate-like second memberbefore bonding the first and second members. This method ensuressufficient performance of the heat dissipation fins. The height of theheat dissipation fins depends on the original thickness of the firstmember and/or the second member. The pitch of the heat dissipation finsdepends on the groove width in cutting between the heat dissipation finsin a process on the first member and/or the second member. Thus, theheight and the pitch of the heat dissipation fins can be freelydetermined independently of each other. That is, both an increase inheight of the heat dissipation fins and a reduction in pitch of the heatdissipation fins can be achieved, thereby making it possible to reduceboth the size and the weight of the heat exchanger while maintainingdesired performance.

The first member may have a recessed portion that is recessed relativeto a surface to which the second member is joined and that is open atthe surface, the corrugated fin plate may be disposed in the recessedportion of the first member, and the second member may be joined to, andoverlaps, the first member such that the corrugated fin plate covers anopening of the recessed portion of the first member while being disposedin the recessed portion. In this configuration, the recessed portion ofthe first member and the second member covering the opening of therecessed portion define the channel in the body.

The body may include: a channel portion in which the corrugated finplate is held between the first member and the second member in thethickness direction; and a header portion which communicates with thechannel portion and in which the corrugated fin plate is not disposed,and the first member or the second member may have a communication holethat penetrates the first member or the second member in the thicknessdirection and communicates with the header.

In the body formed by joining the first member and the second member,the channel portion where the corrugated fin plate is disposed isprovided, and the header portion can also be provided by not disposingthe corrugated fin plate. In addition, the first member or the secondmember has a communication hole that penetrates the first or secondmember in the thickness direction to communicate with the headerportion. Thus, the through hole can serve as an inlet port for allowingcooling target fluid to flow into the header portion or an outlet portallowing cooling target fluid to flow out of the header portion. Thatis, the heat exchanger with this configuration does not need a headermember as a separate member from the body. This is advantageous forreduction in weight of the heat exchanger.

The corrugated fin plate may include a plurality of corrugated finplates, and one of the corrugated fin plates adjacent to the headerportion may have a rigidity higher than those of the other corrugatedfin plates.

With this configuration, a relatively high internal pressure of theheader portion is applied especially to an end of the corrugated finplate adjacent to the header portion, i.e., the corrugated fin platedisposed in the channel portion at the boundary between the headerportion and the channel portion. The corrugated fin plate located atthis location preferably has a high rigidity against the internalpressure. That is, “rigidity” herein refers to rigidity against aninternal pressure.

On the other hand, in the channel portion of the body, the corrugatedfin plate is held between the first member and the second member. Thephrase of “being held between” refers to a situation in which thecorrugated fin plate is sandwiched between the first member and thesecond member with the corrugated fin plate and the first member beingin contact with (especially joined) each of the first and second membersuch that heat can be transmitted between the corrugated fin plate andeach of the first and second members. Thus, the corrugated fin plateslocated at different positions from the corrugated fin plate adjacent tothe header portion do not need to have a high rigidity because thesecorrugated fin plates are held between the first member and the secondmember.

In this manner, the rigidity of the corrugated fin plates may be changeddepending on the location in the body of the heat exchanger. Thisconfiguration enables enhancement of performance of the heat exchangerand/or reduction in weight of the heat exchanger while inhibiting damageof the heat exchanger.

To change the rigidity of the corrugated fin plates, various techniquesmay be employed. For example, the rigidity may be increased byrelatively increasing the thickness of the corrugated fin plates.Alternatively, the rigidity may be increased by reducing the fin pitchof the corrugated fin plates. The rigidity of the corrugated fin platesmay also be changed by changing the types of the corrugated fin plates.The corrugated fin plates requiring a relatively high rigidity are, forexample, plain fin plates, whereas corrugated fin plates allowing arelatively low rigidity may be, for example, perforated fin plateshaving holes in portions of the plain fin plates. The foregoingtechniques may be combined in any manner as necessary.

The header portion may communicate with a bypass valve for allowing thecooling target fluid to bypass the channel.

As described above, in the body formed by joining the first member andthe second member together, the number of header portions and thearrangement thereof may be defined as necessary depending on thearrangement of the corrugated fin plates. As described above, forexample, a header portion disposed at an upstream end of the channel canserve as an inflow header, whereas a header portion disposed at adownstream end of the channel can serve as an outflow header.

The header portion may be disposed at a midpoint of the channel so thata bypass valve communicates with the header portion. Then, the bypassfunction can be incorporated in the heat exchanger. That is, by closingthe bypass valve, cooling target fluid that has flown from the inflowheader into the channel passes through the header portion at a midpointof the channel without change, and reaches the outflow header at adownstream end of the channel. On the other hand, by remaining thebypass valve open, the cooling target fluid that has flown from theinflow header into the channel is allowed to flow out of the body of theheat exchanger from the header portion at a midpoint of the channelthrough the bypass valve. As a result, the cooling target fluid bypassespart of the channel.

Such a bypass function can be utilized for quickly increasing thetemperature of cooling target fluid by avoiding passage of the coolingtarget fluid through part of the channel of the heat exchanger when, forexample, the temperature of the cooling target fluid is below themelting point under a cryogenic temperature environment. The location ofthe bypass valve is not limited to the midpoint of the channel, and thebypass valve may be disposed upstream of the channel so that the fluidbypasses the entire heat exchanger. A plurality of bypass valves may beprovided.

The heat dissipation fins may stand on the outer surface of each of thefirst member and the second member.

This configuration can enhance performance of the heat exchanger andachieve further reduction in size and/or weight of the heat exchanger.

The body may include a channel including a forward channel and abackward channel such that the cooling target fluid flows in oppositedirections in the forward channel and the backward channel, and theforward channel and the backward channel may communicate with each otherin the body.

In the body formed not by extrusion but by joining the first member andthe second member together, the layout of the channel can be relativelyfreely determined. Thus, the channel including the forward channel andthe backward channel that communicate with each other can be formed,thereby eliminating the necessity for attaching a U-turn header to thebody in a subsequent process. This is advantageous for reduction in sizeand/or weight of the heat exchanger.

The body may have a shape constituting part of a conical surface.

In the heat exchanger with this configuration, the first member, thesecond member, and the corrugated fin plates, each having a plate shape,are stacked and joined together, and then bent into, for example, an arcshape. Alternatively, the first member, the second member, and thecorrugated fin plates before being joined may be individually bent, andthen stacked and joined together.

The radius of curvature at one edge perpendicular to the bent directionmay be different from the radius of curvature at the other edge in thebody such that the edge constitutes part of the conical surface.

Advantages of the Invention

As described above, in the heat exchanger for an aircraft engine, thebody of the heat exchanger is formed by stacking the plate-like firstand second members in the thickness direction and joining the first andsecond members together, and the corrugated fin plates are disposed inthe channel in the body. Thus, the height and the pitch of the heatdissipation fins formed on the outer surface(s) of the first memberand/or the second member may be freely determined independently of eachother, thereby enabling reduction in size and weight of the heatexchanger.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view illustrating a heat exchanger for an aircraftengine.

FIG. 2 is a side view illustrating the heat exchanger for an aircraftengine.

FIG. 3 is a disassembled perspective view of the heat exchanger.

FIG. 4 is a front view illustrating a state in which corrugated finplates are disposed in a first member.

FIG. 5 is a sectional view taken along the line V-V in FIG. 1.

FIG. 6 is a sectional view taken along the line VI-VI in FIG. 1.

FIG. 7 is a sectional view taken along the line VII-VII in FIG. 1.

FIG. 8 is a block diagram illustrating a procedure of fabricating a heatexchanger.

DESCRIPTION OF EMBODIMENTS

An embodiment of a heat exchanger for an aircraft engine will bedescribed with reference to the drawings. The following embodiment ismerely an example. FIGS. 1 and 2 illustrate a configuration of a heatexchanger 10. FIG. 1 is a front view of the heat exchanger 10. FIG. 2 isa side view of the heat exchanger 10. Although not shown, the heatexchanger 10 is mounted on an aircraft engine (e.g., a gas turbineengine), and is a heat exchanger for cooling a cooling target fluid thatis lubricating oil of an engine or lubricating oil of a generator drivenby the engine. As clearly illustrated in FIG. 2, the heat exchanger 10is disposed along a curved surface such as an inner peripheral surfaceof a fan casing, for example. The heat exchanger 10 may be disposed atany location. In FIG. 1, the lateral direction in the drawing sheet is adirection along a rotation axis of the gas turbine engine, and thevertical direction in the drawing sheet is a circumferential direction.The illustrated heat exchanger 10 has a circumferential length that isabout ⅛ of the entire circumference thereof. In FIG. 1, the left side inthe drawing sheet corresponds to an upstream side of an airflow flowingin the gas turbine engine, and the right side in the drawing sheetcorresponds to a downstream side of the airflow. Thus, the heatexchanger 10 is exposed to the air flowing from the left to the right inthe drawing sheet. As illustrated in FIGS. 5 to 7, the radius ofcurvature of the edge at the upstream side of the arcuate heat exchanger10 is smaller than the radius of curvature of the edge at the downstreamside. The chain lines in FIGS. 5 to 7 indicate the horizon. The heatexchanger 10 has a shape constituting part of a conic surface as awhole.

FIG. 3 is a disassembled perspective view of the heat exchanger 10. Inthe heat exchanger 10, a plurality of corrugated fin plates 3 aredisposed in a body 100 in which a first member 1 and a second member 2are stacked in a thickness direction. In other words, the heat exchanger10 is a stack of three members: the first member 1; the second member 2;and the corrugated fin plates 3, which are arranged in the thicknessdirection and bonded together by, for example, brazing. The heatexchanger 10 is made of, for example, aluminium or an aluminium alloy.Materials for the heat exchanger 10 are not specifically limited. Theheat exchanger 10 may be made of various materials such as stainlesssteel, titanium, copper, or inconel.

The first member 1 is a rectangular plate-like member, and in theillustrated example, the circumferential length is larger than the axiallength, i.e., the first member 1 has a band shape as a whole. The innersurface (i.e., the surface shown in FIG. 3) of the first member 1 has arecessed portion 11 that is recessed relative to the surface thereof.The recessed portion 11 has a predetermined rectangular shape except forthe outer rim of the first member 1 that is rectangular as a whole. Thatis, the first member 1 having the recessed portion 11 has a bathtubshape. The recessed portion 11 defines part of a channel 4 for coolingtarget fluid formed in the body 100, which will be described later. Thecorrugated fin plates 3 are disposed in the recessed portion 11.

As illustrated in FIGS. 3 and 4, a separator 12 is formed at the axialmiddle of the recessed portion 11 and extends from a circumferential end(i.e., the top in FIG. 4) to the other circumferential end (i.e., thebottom in FIG. 4) of the separator 12. The separator 12 divides thechannel 4 for cooling target fluid into a forward channel 41 and abackward channel 42, which will be specifically described later. Thearrows in FIG. 4 indicate the flow of cooling target fluid. Theseparator 12 extends halfway in the circumferential direction in therecessed portion 11. At the other end in the recessed portion 11, theforward channel 41 and the backward channel 42 communicate with eachother. The channel 4 for cooling target fluid defined by the recessedportion 11 and the separator 12 has a U-shape as a whole.

Grooves 13 and 14 are formed in a circumferential end of the recessedportion 11. The grooves 13 and 14 axially extend at both axial ends withthe separator 12 sandwiched therebetween. As clearly illustrated in FIG.5, the grooves 13 and 14 are deeper than the recessed portion 11. Thegroove 13 located closer to the forward channel 41 than the groove 14constitutes an inflow header 43 allowing cooling target fluid to flowinto the channel 4, together with a groove 27 of the second member 2,which will be described later. The groove 14 located closer to thebackward channel 42 than the groove 13 constitutes an outflow header 44allowing cooling target fluid to flow out of the channel 4, togetherwith a groove 28 of the second member 2, which will be described later.

Grooves 15 and 16 similar to the grooves 13 and 14 are formed in acircumferential middle of the recessed portion 11 (see also FIG. 7).Specifically, the grooves 15 and 16 axially extend at both axial endswith the separator 12 sandwiched therebetween. The grooves 15 and 16 aredeeper than the recessed portion 11. The two grooves 15 and 16constitute bypass headers 45 and 46 for bypassing part of the channel 4of the heat exchanger 10, together with grooves 213 and 214 of thesecond member 2, which will be described later.

A large number of heat dissipation fins 17 stand on the outer surface(i.e., the left surface in the drawing sheet of FIG. 2 and the topsurface in the drawing sheets of FIGS. 5-7) of the first member 1. InFIGS. 1-3, a region where the heat dissipation fins 17 are disposed isindicated by chain lines, and some of the heat dissipation fins 17 arenot shown. The heat dissipation fins 17 are axially arranged on thesubstantially overall outer surface of the first member 1. The finheight and the fin pitch of the heat dissipation fins 17 areappropriately defined.

In a manner similar to the first member 1, the second member 2 is arectangular plate-like member, and in the illustrated example, thecircumferential length is larger than the axial length, i.e., the secondmember 2 has a band shape as a whole. No recessed portions are formed inthe inner surface of the second member 2. The second member 2 has a lidshape that covers the bathtub-shaped first member 1. A port attachmentpart 21 to which a port member 51 as a unit of an inlet port 511 and anoutlet port 512 is attached and a valve attachment part 22 to which abypass valve 6, which will be specifically described later, is attachedare formed on the outer surface (i.e., the surface shown in FIG. 3) ofthe second member 2.

The port attachment part 21 is located at a circumferential end of thesecond member 2. As illustrated in FIGS. 1 and 5, the port attachmentpart 21 has two through holes 23 and 24 penetrating the port attachmentpart 21 in the thickness direction and arranged side by side in theaxial direction.

Two protrusions 25 and 26 are formed on the outer surface of the secondmember 2 and axially extend at both axial ends with the port attachmentpart 21 sandwiched therebetween. As illustrated in FIG. 5, theprotrusions 25 and 26 respectively have grooves 27 and 28 in the innersurface (i.e., the upper surface in FIG. 5) of the second member 2. Thegroove 27 formed in the protrusion 25 communicates with the through hole23 of the port attachment part 21. The groove 28 formed in theprotrusion 26 communicates with the through hole 24 of the portattachment part 21. When the second member 2 overlaps the first member1, the grooves 27 and 28 respectively face the grooves 13 and 14 of thefirst member 1 and define the inflow header 43 and the outflow header44. As illustrated in FIG. 5, each of the inflow header 43 and theoutflow header 44 is thicker than the channel 4 (see also FIG. 6).

As described above, the port member 51 attached to the port attachmentpart 21 has the inlet port 511 and the outlet port 512. The inlet port511 communicates with the through hole 23 of the port attachment part21, and the outlet port 512 communicates with the through hole 24 of theport attachment part.

The inlet port 511 is connected to a piping (not shown), and coolingtarget fluid is supplied through the piping and flows into the channel 4(i.e., the forward channel 41) in the body 100 through the inlet port511, the through hole 23, and the inflow header 43. Cooling target fluidthat has passed through the channel 4 (i.e., the backward channel 42) inthe body 100 flows out of a piping (not shown) connected to the outletport 512 through the outflow header 44, the through hole 24, and theoutlet port 512.

The valve attachment part 22 is located at a circumferential middle ofthe second member 2. As illustrated in FIGS. 1 and 7, the valveattachment part 22 also has two through holes 29 and 210 penetrating thevalve attachment part 22 in the thickness direction.

In a manner similar to both ends of the port attachment part 21, twoprotrusions 211 and 212 are formed at both axial ends sandwiching thevalve attachment part 22. As illustrated in FIG. 7, the protrusions 211and 212 respectively have grooves 213 and 214 in the inner surface(i.e., the upper surface in FIG. 7) of the second member 2. The groove213 formed in the protrusion 211 communicates with the through hole 29of the valve attachment part 22. The groove 214 formed in the protrusion212 communicates with the through hole 210 of the valve attachment part22.

When the second member 2 overlaps the first member 1, the grooves 213and 214 respectively face the grooves 15 and 16 of the first member 1,and define the bypass header 45 close to the forward channel 41 and thebypass header 46 close to the backward channel 42. Thus, the throughhole 29 communicates with the bypass header 45 close to the forwardchannel 41, and the through hole 210 communicates with the bypass header46 close to the backward channel 42. As illustrated in FIG. 7, each ofthe bypass headers 45 and 46 is thicker than the channel 4 (see alsoFIG. 6).

A large number of heat dissipation fins 215 are circumferentiallyarranged at a predetermined pitch and stand substantially on the overallsurface of the outer surface of the second member 2 except the portattachment part 21 and the valve attachment part 22. The fin height andthe fin pitch of the heat dissipation fins 215 are appropriatelydefined. A region where the heat dissipation fins 215 of the secondmember 2 is also indicated by chain lines and some of the heatdissipation fins 215 are not shown in the drawings.

Now, a configuration of the bypass valve 6 attached to the valveattachment part 22 will be briefly described with reference to FIG. 7.In this example, the bypass valve 6 is a differential pressure shut-offvalve, and opens and closes in accordance with a differential pressurebetween the bypass header 45 and the bypass header 46. The bypass valve6 includes a valve casing 61 attached to the valve attachment part 22.The valve casing 61 includes an inflow chamber 62 that communicates withthe through hole 29 of the valve attachment part 22 and an outflowchamber 63 that communicates with the through hole 210 of the valveattachment part 22. The inflow chamber 62 and the outflow chamber 63communicate with each other through a communication hole 621. The inflowchamber 62 incorporates a valve mechanism. The valve mechanism includesa cylindrical valve body 64, a valve 66 seated on a valve seat 65 formedon the valve body 64, and a compression coil spring 67 that biases thevalve 66 to a closed side. The cylindrical valve body 64 has one openend in the axial direction (i.e., the vertical direction in FIG. 7) ofthe cylinder in which the valve seat 65 is formed. An opening forallowing the inside and outside of the valve body 64 to communicate witheach other is provided in the circumferential surface of the valve body64. In this manner, the through hole 29 of the valve attachment part 22communicates with the through hole 210 through the valve seat 65, theinside of the valve body 64, the communication hole 621, and the outflowchamber 63.

The valve 66 is seated on the valve seat 65 of the valve body 64, and isconfigured to reciprocate in the cylinder axial direction of the valvebody 64. The bypass valve 6 is opened or closed by switching between astate in which the valve 66 is seated on the valve seat 65 and a statein which the valve 66 is separated from the valve seat 65. When thebypass valve 6 is open, the through hole 29 and the through hole 210 inthe valve attachment part 22 communicate with each other through thebypass valve 6. That is, the two bypass headers 45 and 46 in the body100 communicate with each other through the outside of the body 100. Onthe other hand, when the bypass valve 6 is closed, the communicationbetween the through hole 29 and the through hole 210 in the valveattachment part 22 is stopped. Consequently, the two bypass headers 45and 46 in the body communicate with each other only through the channel4 in the body 100.

The compression coil spring 67 is disposed to be externally fitted ontothe shaft of the valve 66, and biases the valve 66 such that the valve66 is pressed against the valve seat 65. In this manner, the bypassvalve 6 is open when the differential pressure between the bypass header45 and the bypass header 46 is a predetermined pressure or more, and isclosed when the differential pressure between the bypass header 45 andthe bypass header 46 is lower than the predetermined pressure. When thebypass valve 6 is closed, cooling target fluid that has flown into theforward channel 41 through the inflow header 43 passes through thebypass header 45, reaches the backward channel 42, and then flows intothe outflow header 44 through the bypass header 46 of the backwardchannel 42. When the bypass valve 6 is closed, the two bypass headers 45and 46 function as mixing headers provided at a midpoint of the forwardchannel 41 or the backward channel 42. That is, in each of the bypassheaders 45 and 46, the cooling target fluid is mixed so that temperaturedistribution can be made uniform, thereby enhancing the performance ofthe heat exchanger 10.

On the other hand, when the bypass valve 6 is opened, cooling targetfluid that has flown into the forward channel 41 through the inflowheader 43 passes through the bypass valve 6 from the bypass header 45,flows in the bypass header 46 near the backward channel 42, and reachesthe outflow header 44. When the bypass valve 6 is open, cooling targetfluid bypasses part of the channel 4. Such a bypass function can beutilized for quickly increasing the temperature of cooling target fluidby avoiding passage of the fluid through part of the channel 4 of theheat exchanger 10 when, for example, the temperature of the coolingtarget fluid is below the melting point under a cryogenic temperatureenvironment. As described above, the bypass valve is not limited to apressure-responsive valve including a compression coil spring, and maybe another type of pressure-responsive valve. Alternatively, atemperature-responsive valve may be employed.

As illustrated in FIGS. 3 and 4, the corrugated fin plates 3 aredisposed at predetermined locations in the recessed portion 11 of thefirst member 1. The corrugated fin plates 3 divide the channel 4 forcooling target fluid into a plurality of channels connected from theinflow header 43 to the outflow header 44, and enlarges the heattransfer area. As plainly illustrated in FIG. 6, the corrugated finplates 3 disposed in the recessed portion 11, i.e., in the channel 4,are sandwiched between the first member 1 and the second member 2 andjoined to the inner surfaces of the first member 1 and the second member2.

The corrugated fin plates 3 include a plurality of corrugated fin plates3 having predetermined shapes in accordance with the locations. In theillustrated example, the corrugated fin plates 3 include: six relativelysmall rectangular corrugated fin plates 3 (corresponding to relativelyrigid plates 31, which will be described later); two relatively largerectangular corrugated fin plates 3; two trapezoidal corrugated finplates 3, and an approximately triangular corrugated fin plate 3. Therectangular corrugated fin plates 3 are disposed in the forward channel41 or the backward channel 42. The triangular corrugated fin plate 3 isdisposed at the location where the forward channel 41 and the backwardchannel 42 communicate with each other. The trapezoidal corrugated finplates 3 are disposed between the rectangular corrugated fin plates 3and triangular corrugated fin plate 3.

The corrugated fin plates 3 include relatively rigid plates 31 andrelatively less rigid plates 32. The relatively rigid plates are plainfin plates 31 in this example. On the other hand, the relatively lessrigid plates are perforated fin plates 32 in which through holes areformed at predetermined locations in the plain fin plate in thisexample.

As illustrated in FIG. 4, the plain fin plates 31 are located adjacentto the grooves 13, 14, 15, and 16 in the recessed portion 11 of thefirst member 1. These locations adjacent to the grooves 13, 14, 15, and16 correspond to the location adjacent to the downstream side of theinflow header 43, the location adjacent to the upstream side of theoutflow header 44, the locations adjacent to the upstream side and thedownstream side of the bypass header 45 near the forward channel 41, andthe locations adjacent to the upstream side and the downstream side ofthe bypass header 46 near the backward channel 42, respectively, in thebody 100 of the heat exchanger 10. On the other hand, the perforated finplates 32 are located at locations except locations where the plain finplates 31 are disposed.

Referring now to FIG. 8, a procedure of fabricating the heat exchanger10 with the above-described configuration will be described. Thefabrication procedure roughly includes a formation process (P81 and P82)of the first member 1, a formation process (P83 and P84) of the secondmember 2, a formation process (P85 and P86) of the plain fin plates 31,a formation process (P87 and P88) of the perforated fin plates 32, andan assembly process (P89, P810, P811, and P812).

First, in the formation process of the first member 1, at P81, a platemember with a predetermined shape is prepared. The plate member onlyneeds to a flat plate member with a predetermined thickness. Thethickness of the plate member depends on the height of the heatdissipation fins 17 standing on the outer surface of the first member 1.Since the body 100 is to be processed by bending the body 100 into aconical shape, the flat plate member has a trapezoidal shape, which willbe specifically described later. Then, at P82, the plate member issubjected to cutting, thereby forming the heat dissipation fins 17, therecessed portion 11, and the grooves 13, 14, 15, and 16. The fin pitchof the heat dissipation fins 17 is determined depending on the groovewidth in cutting between the fins. As described above, since the body100 is to be bent into a conical shape, the heat dissipation fins 17that are circumferentially arranged side by side are not parallel toeach other. In this manner, a flat first member 1 is completed.

In a manner similar to P81, in the formation process of the secondmember 2, at P83, a plate member with a predetermined shape is prepared.The plate member is a flat plate member whose thickness corresponds tothe fin height of the heat dissipation fins 215. The plate member isalso trapezoidal. Then, at P84, the plate member is subjected tocutting, thereby forming the heat dissipation fins 215, the portattachment part 21, the valve attachment part 22, the protrusions 25,26, 211, and 212, and the grooves 27, 28, 213, and 214. The heatdissipation fins 215 that are circumferentially arranged side by sideare not parallel to each other. In this manner, a flat second member 2is completed.

In the formation process of the plain fin plates 31, at P85, plain finplates 31 are formed at a predetermined pitch with a known method. Then,at P86, the fin plates 31 are cut into predetermined shapes, i.e.,predetermined rectangular shapes as illustrated in FIGS. 3 and 4. Anecessary number of plain fin plates 31 with the predetermined shapesare prepared. The corrugated fin plates 31 are also flat.

Similarly, in the formation process of the perforated fin plates 32, atP87, perforated fin plates 32 are formed at a predetermined pitch with aknown method. Then, at P88, the fin plates 32 are cut into predeterminedshapes. Necessary numbers of the rectangular, trapezoidal, andtriangular perforated fin plates 32 are prepared. The corrugated finplates 32 are also flat.

In this manner, the first member 1, the second member 2, and thecorrugated fin plates 31 and 32 are prepared. Then, in the assemblyprocess, as illustrated in FIGS. 3 and 4, the corrugated fin plates 31and 32 are disposed in the recessed portion 11 of the first member 1,and the second member 2 overlaps the first member 1 such that theopening of the recessed portion 11 is covered (at P89). At this time, asillustrated in FIG. 3, a plate-shaped brazing filler metal with apredetermined shape (i.e., three types of plates 71, 72, and 73 in theillustrated example) is interposed between the first member 1 and eachof the corrugated fin plates 31 and 32 and between the second member 2and each of the corrugated fin plates 31 and 32. Although the membersare bent in FIG. 3, the members are flat at P89 in the fabricationprocedure illustrated in FIG. 8.

Thereafter, at P810, the first member 1, the corrugated fin plates 31and 32, and the second member 2 are integrated by brazing. Theintegrated member (i.e., the body 100) is flat. Subsequently, at P811,the integrated ember is bent into a predetermined conic shape.

Then, at P812, members such as a port member 51 and a bypass valve 6 areattached to the bent body 100, thereby completing a heat exchanger 10.

In the heat exchanger 10, the body 100 is formed by stacking and joiningthe plate-like first and second members 1 and 2 in the thicknessdirection. Thus, each of the heat dissipation fins 17 standing on theouter surface of the first member 1 and the heat dissipation fins 215standing on the outer surface of the second member 2 can be formed bycutting the plate members as described above. In such a process, the finheights of the heat dissipation fins 17 and 215 depend on thethicknesses of the plate members, and the fin pitches of the heatdissipation fins 17 and 215 depend on the groove widths in cuttingbetween the fins. Thus, the heights and the pitches of the heatdissipation fins 17 and 215 can be freely determined independently ofeach other. This determination enables both an increase in height of theheat dissipation fins 17 and 215 and a reduction in pitch of the heatdissipation fins 17 and 215. As a result, the heat exchanger 10 can bemade small and lightweight while maintaining desired performance. Theheat dissipation fins 17 and 215, of course, are integrated with thebody 100 such that heat is transmitted therebetween.

The body 100 configured by joining the first member 1 and the secondmember 2 includes not only the channel 4 provided with the corrugatedfin plates 31 and 32 but also the inflow header 43 and the outflowheader 44 provided with no corrugated fin plates 31 and 32. A separateheader member does not need to be attached to the body 100. Thisconfiguration can further reduce the weight of the heat exchanger 10.

In the body 100 configured by joining the first member 1 and the secondmember 2, the layout of the channel 4 for cooling target fluid can berelatively freely determined. In the heat exchanger 10 with theabove-described configuration, the separator 12 is provided in therecessed portion 11, thereby forming a U-turn channel including theforward channel 41 and the backward channel 42. In particular, in theabove-described configuration, a portion allowing the forward channel 41and the backward channel 42 to communicate with each other is alsoprovided in the body 100. Thus, no separate U-turn header needs to beattached to the body 100. This configuration is also advantageous forreduction in weight of the heat exchanger 10.

In addition, a header can be disposed at any location in the body 100.In the above-described configuration, the bypass headers 45 and 46 areprovided at a midpoint of the forward channel 41 and a midpoint of thebackward channel 42, respectively. Thus, the bypass function of allowingcooling target fluid to bypass part of the channel 4 of the heatexchanger 10 can be incorporated without inhibiting reduction in weight.A header to which a bypass valve is attached is not necessarily providedin a midpoint of the channel, and may be located upstream of the channelsuch that cooling target fluid can bypass the entire heat exchanger 10.Alternatively, a plurality of bypass headers may be provided such thatbypass valves are individually attached to the headers.

As illustrated in FIG. 6, the corrugated fin plates 31 and 32 in thebody 100 are held between the first member 1 and the second member 2 inthe thickness direction. Specifically, the corrugated fin plates 31 and32 are joined to the inner surface of the first member 1 and the innersurface of the second member 2, respectively, by brazing.

The corrugated fin plates 31 adjacent to the inflow header 43, theoutflow header 44, and the bypass headers 45 and 46, and particularlyends of the plates 31, are subjected to an internal pressure of theheader, and the fins might be damaged. To avoid such damage, in theabove-described configuration, the corrugated fin plates 31 locatedadjacent to the headers 43, 44, 45, and 46 have an increased rigidityagainst the internal pressure of the header. In this manner, damage ofthe corrugated fin plates 31 can be prevented. This reduces degradationof performance of the heat exchanger 10.

On the other hand, the corrugated fin plates 32 located except for thelocations adjacent to the headers 43, 44, 45, and 46 are perforated finplates. Thus, the performance of the heat exchanger 10 can be enhancedand the weight of the heat exchanger 10 can be reduced. Although theperforated fin plates divide the channel 4 into a plurality of channels,the channels communicate with each other through holes. Thus, even ifone of the channels were blocked, cooling target fluid can flow throughthe channels (specifically, bypasses the blocked channel). In thismanner, degradation of performance of the heat exchanger 10 can beadvantageously reduced.

In the body 100 configured by the first member 1 and the second member2, not only the plain and perforated corrugated fin plates, but alsovarious types of corrugated fin plates may be disposed. Thisconfiguration can enhance the degree of freedom in designing the heatexchanger 10.

In the above-described configuration, both the first member 1 and thesecond member 2 include the heat dissipation fins 17 and 215.Alternatively, only one of the first member 1 or the second member 2 mayinclude heat dissipation fins.

In the above-described configuration, only the first member 1 has therecessed portion 11. Alternatively, both the first member 1 and thesecond member 2 may have recessed portions so that the two recessedportions form the channel in the body 100 when the first member 1 andthe second member 2 overlap each other.

The channel 4 in the body 100 does not need to have a U-shape includingthe forward channel 41 and the backward channel 42. An inflow header maybe provided at one circumferential end of the body 100 with an outflowheader being provided at the other circumferential end of the body 100so as to form a channel in which cooling target fluid flows in onedirection from one end to the other along the circumference. The bypassfunction is not necessary and may be omitted. In the configuration inwhich the inflow header is provided at one circumferential end of thebody 100 and the outflow header is provided at the other circumferentialend of the body 100, the bypass header can be provided at a midpoint inthe circumferential direction. In this case, the bypass header functionsas a header for causing cooling target fluid to flow out of the body 100from the midpoint of the channel 4.

As described above, changing the rigidity of the corrugated fin platesis not necessarily achieved by employing the plain fin plates and theperforated fin plates as described above. Other types of corrugated finplates may be employed as necessary. Instead of changing the types ofthe corrugated fin plates, the thickness of the corrugated fin platesmay be changed. Specifically, in a portion requiring a relatively highrigidity, thick corrugated fin plates are employed, whereas in a portionallowing a relatively low rigidity, thin corrugated fin plates may beemployed. The rigidity may also be changed by changing the fin pitch ofthe corrugated fin plates. Specifically, in a portion requiring arelatively high rigidity, corrugated fin plates arranged at a small finpitch are employed, whereas in a portion allowing a relatively lowrigidity, corrugated fin plates arranged at a large fin pitch may beemployed.

In the above-described configuration, bending is performed afterstacking and joining the first member 1, the second member 2, and thecorrugated fin plates 3. Alternatively, after the first member 1, thesecond member 2, and the corrugated fin plates 3 have been individuallybent, the first member 1, the second member 2, and the corrugated finplates 3 may be stacked and joined together.

INDUSTRIAL APPLICABILITY

The heat exchanger disclosed herein is especially useful as a heatexchanger installed in an aircraft engine and used for coolinglubricating oil of an engine or a generator by using an airflow passingthrough the engine.

DESCRIPTION OF REFERENCE CHARACTERS

-   -   10 heat exchanger    -   100 body    -   1 first member    -   11 recessed portion    -   17 heat dissipation fin    -   2 second member    -   215 heat dissipation fin    -   23 through hole (communication hole)    -   24 through hole (communication hole)    -   29 through hole (communication hole)    -   210 through hole (communication hole)    -   3 corrugated fin plate    -   31 plain fin plate    -   32 perforated fin plate    -   4 channel (channel portion)    -   41 forward channel    -   42 backward channel    -   43 inflow header (header portion)    -   44 outflow header (header portion)    -   45 bypass header (header portion)    -   46 bypass header (header portion)    -   6 bypass valve

The invention claimed is:
 1. A heat exchanger for an aircraft engine,the heat exchanger being disposed along a curved surface in the aircraftengine and configured to cool cooling target fluid when being exposed toan airflow flowing in the engine, the heat exchanger comprising: a bodyincluding a plate-like first member and a plate-like second member thatare stacked in a thickness direction of the first and second members andjoined together, and a channel which is defined in the body and in whichthe cooling target fluid flows; and a plurality of corrugated fin platesdisposed in the channel in the body, wherein the body is bent along thecurved surface, a plurality of heat dissipation fins stand on an outersurface of at least one of the first member or the second member, thefirst member has a recessed portion that is recessed relative to asurface to which the second member is joined and that is open at thesurface, the corrugated fin plates are disposed in the recessed portionof the first member, the second member is joined to, and overlaps, thefirst member, and covers an opening of the recessed portion of the firstmember while the corrugated fin plates are disposed in the recessedportion, the body includes: a channel portion in which the corrugatedfin plates disposed in the recessed portion are held between the firstmember and the second member in the thickness direction; and a headerportion which communicates with the channel portion and is disposedbetween the first member and the second member, wherein the corrugatedfin plates are disposed between the first and second members in therecessed portion without extending to the header portion, the firstmember or the second member has a communication hole that penetrates thefirst member or the second member in the thickness direction andcommunicates with the header portion, and the corrugated fin platesinclude a plain fin plate and a perforated fin plate, the plain finplate is adjacent to the header portion, and the perforated fin plate isnot adjacent to the header portion, and the plain fin plate adjoins theperforated fin plate in the recessed portion.
 2. The heat exchanger ofclaim 1, wherein the header portion communicates with a bypass valveconfigured to allow the cooling target fluid to bypass the channel. 3.The heat exchanger of claim 2, wherein the header portion is disposed ata midpoint of the channel.
 4. The heat exchanger of claim 1, wherein theheat dissipation fins stand on the outer surface of each of the firstmember and the second member.
 5. The heat exchanger of claim 1, whereinthe body includes a channel including a forward channel and a backwardchannel such that the cooling target fluid flows in opposite directionsin the forward channel and the backward channel, and the forward channeland the backward channel communicate with each other in the body.
 6. Theheat exchanger of claim 1, wherein the body has a shape constitutingpart of a conical surface.
 7. The heat exchanger of claim 1, wherein theplain fin plate and the perforated fin plate allow the cooling targetfluid to flow in the same direction.
 8. The heat exchanger of claim 1,wherein the perforated fin plate is prepared by forming through holes inthe plain fin plate.
 9. The heat exchanger of claim 8, wherein the plainfin plate is joined to the first and second members, and the perforatedfin plate is joined to the first and second members.